Title: Influence of rock mass rating and in situ stress on stability of roof rock in bord and pillar development panels

Authors: R.K. Sinha; M Jawed; S Sengupta

Addresses: Department of Mining Engineering, Indian School of Mines, Dhanbad 826 004, Jharkhand, India ' Department of Mining Engineering, Indian School of Mines, Dhanbad 826 004, Jharkhand, India ' Geotechnical Engineering Department, National Institute of Rock Mechanics, ITI Bhavan Annex building, Old Madras Road, Doorvani Nagar, Bangalore 560 016, Karnataka, India

Abstract: The re-orientation of bord and pillar layout is dictated by the direction of the horizontal stress. However, the competence of strata expressed in terms of rock mass rating (RMR) and the magnitude of in situ stress have a persuasive influence in deciding the gain out of re-orientation of galleries. However, a few queries like: a) "Is it essential to re-orient all bord and pillar workings vis-à-vis the direction of in situ stress?"; b) "What if the strata are competent and the workings are subjected to low magnitude of horizontal stress?"; c) "What happens to a bord and pillar workings affected by high horizontal stress and having incompetent strata?" have remained unaddressed. This paper, therefore, addresses such queries through a new approach of classification of the bord and pillar development workings using numerical modelling. This classification system will aid field engineers in deciding the need for re-orienting galleries vis-à-vis the RMR and in situ stress.

Keywords: bord and pillar layout; development panels; in situ stress; perturbed stress; rock mass rating; RMR; Sheorey's failure criterion; horizontal stress; roof rock stability; numerical modelling; gallery reorientation; underground mining; coal mines.

DOI: 10.1504/IJMME.2015.071175

International Journal of Mining and Mineral Engineering, 2015 Vol.6 No.3, pp.258 - 275

Accepted: 06 May 2015
Published online: 13 Aug 2015 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article